Process for sizing paper and product therefrom



Patented Dec. 1, 1931 EDWARD J. JOHNSTONE, OF LOCKPORT, NEW YORK PROCESS FOR'SIZING PAPER AND PRODUCT THEREFROM No Drawing. Original application filed November 29, 1929, Serial No. 410,656. Divided and this application filed January 27, 1930. Serial No. 423,902.

As set forth in my co-pending United States patent application, bearing Serial Number 410,656, and filed November 29, 1929,

' I have discovered a means for producing a substantially anhydrous sizing composition composed of rosin and alkali metals, and of which the present application is a division.

I have found that numerous advantages accrue in theprocess of sizing fibrous materials by means of the hereinbefore-mentioned substantially anhydrou's'sizing composition, which constitute an advance over prior art in a number of ways.

According to prior art, rosin size is shipped with a water content of at least forty percent,

byweight, which necessitates a highly specialized and elaborate emulsifying device. This device exists in a number of forms but possesses the following inherent disadvantages.

These just-mentioned emulsifying devices re quire a very careful and exact setting of their operating parts, which almost invariably get out of adjustment, causing badly emulsified sizing material to be mixed with 2 the fibrous products which are to be sized.

Furthermore, they require steam in their operation and also necessitate supervision by a skilled operative.

Another great disadvantage inherent in the emulsification of wet rosin size lies in the fact that it is difficult to maintain a uniform ratio in the emulsifier between the wet rosin size and the hot Water and steam which is used to dilute the said wet rosin size to a lower concentration. This fact frequently results in a Wide variation of the final solid content of the diluted wet rosin size. As hereinbefore stated, the wet rosin size may contain approximately sixty percent of solids and, when diluted down by the action of the emulsifier, will contain three percent of solids, more or less. As is obvious, unless the emulsifier consistently feeds the same proportion of wet rosin size to the hot water and steam, variations in the finely diluted size solution inevitably occur.

The reason for diluting the wet rosin size, as hereinbefore described, resides in the fact that, if the wet rosin size containing approximately sixty percent of solids is added directly to the fibres during the well-known beating process, then and in that event, the size is very refractory to homogeneous dispersion through the fibre and water mass. This just-mentioned pasty rosin size accumulates between the bars in the bed plate of the beater, on the side of the back fall opposite the beater roll, etc., and, as a result, produces a very disastrous condition of inhomogeneity in the beater contents, which shows when'the pulp is finally formed and fabricated. In short, the hereinbefore-mentioned process of emulsifying wet rosin size is, as it were, to subdivide to a dilute colloidal condition the solid materials of the concen-- trated rosin size. e

The object of this invention is to obviate the use of emulsifying devices and to permit of directly adding finely comminuted substantially anhydrous rosin size directly to the fibre and water suspension in the beater, Jordan, clafiin, stuff chest or head box.

In carrying out my invention, I take the desired quantity of the finely comminuted substantially anhydrous rosin size, made according to the method set forth in my copending United States patent application, Serial Number 410,656 and add this material directly to the beater, Jordan, elaflin, stufi' chest or head box. I then thoroughly mix and disperse to colloidal dimensions the justmentioned comminuted substantially anhydrous rosin size. I then precipitate the resin size upon the hereinbefore-mentioned fibres by the addition of sulphate of alumina, the alums, or other known precipitating media. I then form the sized fibres according to any known means, such as on a paper machine of any known type, or upon a rotary filteryor any other type of machine used to form molded compositions of fibrous materials in general, and of cellulosic fibrous materials in particular.

Without in any way departing from the scope of my invention I may use any known mechanical device for feeding the hereinbefore-mentioned substantially anhydrous comminuted rosin size to the fibre and Water suspension, such as a hopper, a bucket elevator, a screw conveyor, etc.

By sizing fibrous products, I mean the process of incorporating therein and presumably forming a colloidal adsorption or quasi-chemical reaction between the fibres and precipitated rosin size to produce formed and molded compositions of matter consistmg, Wholly or in part, of fibres that are substantially water-repellent, less susceptible to the efiects of moisture, possessing a harder and more crackly feel, together with the other Well-known attributes of properly sized fibrous materials.

I claim:

1. A process for sizing fibrous materials comprising adding thereto substantially anhydrous finely comminuted rosin size While the fibres are suspended in water at ordinary temperature.

2. A process for sizing fibrous materials comprising adding to suspensions of fibrous material in Water substantially anhydrous finely comminuted rosin size, mixing with the Water to disperse the size, and precipitating the dispersed size.

3. A process for sizing fibrous materials comprising adding finely comminuted substantially anhydrous rosin size to suspensions of the fibrous materials in Water, mixing and dispersing the rosin size to a colloidal solution, and subsequently precipitating the rosin size With a metallicsalt. I

EDWARD J. JOHNSTONE. 

